Keeping the Camera out of meshes in the BGE
Is there any simple way to have a camera act as a slow parent to an object yet still not go through meshes?


But the answer is ... there is no build-in solution. This is because any solution would be a specific solution to your game. So you need to develop your own feature.

Btw. slow parent does not matter in that situation.

Examples:


Perform a ray test from target to the camera. Set the camera on any hitpoint discovered. This way the camera will be behind blocking objects.
Perform collision test at the sides of the camera's view. Let the camera orbit around the target to avoid blocked views (see FreeView).